The purpose of this core is to provide support for he acquisition and analysis of the biological measures that are common across projects. Biological measures that are project-unique (e.g., imaging and lesioning techniques) will be supported through project resources. All four of the projects make use of this core. There are several types of biological measures that will be used in common across two or more projects. These include measures of brain electrical activity (all projects), cardiovascular activity including impedance cardiography, emotion-modulated startle and cortisol from plasma or saliva (all projects). Details are presented on the methods for recording and analyzing these common measures.